原状和重塑湖泊相软黏土动力特性宏微观试验研究  

Macroscopic and microscopic test study on dynamic characteristics of undisturbed and remolded lacustrine soft clay

作　　者：李雨润 朱皓旸 张静娟 LI Yurun;ZHU Haoyang;ZHANG Jingjuan(School of Civil Engineering and Transportation,Hebei Universily of Technology,Tianjin 300401,China;Civil Engineering Technology Research Center of Hebei Province,Tianjin 300401,China)

机构地区：[1]河北工业大学土木与交通学院,天津300401 [2]河北省土木工程技术研究中心,天津300401

出　　处：《世界地震工程》2024年第2期100-111,共12页World Earthquake Engineering

基　　金：国家自然科学基金资助项目(52278340,51778207);河北省自然科学基金资助项目(E2023202028);中国地震局工程力学研究所基本科研业务费专项资助项目(2021D02)。

摘　　要：为了对比衡水湖附近原状和重塑湖泊相软黏土的动力特性差异,利用GZZ-50B型共振柱仪对原状和重塑湖泊相软黏土分别进行动力特性试验,采用Davidenkov本构模型对试验获得的动力特性参数进行拟合,绘制了G-γ、λ-γ和G/G_(max)-γ关系曲线,并将所得的动力特性统计值与其他学者给出的动力特性推荐值进行了对比,通过SEM电镜测量了共振柱试验前后的微观结构,并分析了微观结构参数的变化规律。结果表明:当固结围压相同时,原状湖泊相软黏土的G-γ曲线始终高于重塑土,而原状土的λ-γ曲线始终低于重塑土;当动剪应变较大时,原状土的动剪切模量G会急剧下降并接近重塑土;原状和重塑土的G_(max)相对差值、G/G_(max)-γ和λ-γ拟合曲线差异会随着固结围压的增大而减小;通过与其他学者研究成果对比,发现沉积相并不是土体动力特性的决定性因素,同一沉积相但不同地区的软黏土动力特性也会有所差异。通过对微观结构参数的定量分析发现:随着固结围压的增加,原状土颗粒和孔隙的面积平均值以及最大直径平均值均有所下降,而重塑土差异并不明显,且微观结构参数相对差值与最大动剪切模量G_(max)相对差值呈正相关的关系;经过共振柱试验后,原状湖泊相软黏土的大、中颗粒和孔隙转变为小、微颗粒和孔隙,较大的片状结构和团聚体结构减少,原状土微观结构参数接近于重塑土,从微观角度解释了宏观土动力学特性。In order to compare the difference between the dynamic characteristics of undisturbed and remolded lacustrine soft clay near Hengshui Lake,this paper uses GZZ-50B resonance column instrument to carry out dynamic characteristics tests on the undisturbed and remolded lacustrine soft clay respectively,adopts Davidenkov constitutive model to fit the dynamic characteristics parameters obtained by the tests,and draws the relationship curves of G-γ,λ-γand G/G_(max)-γ,and the obtained dynamic characteristic statistical values were compared with the recommended values given by other scholars.The microstructure before and after the resonance column test is measured by SEM electron microscopy,and the change regularity of microstructure parameters is analyzed.The results show that when the consolidation confining pressure is the same,the G-γcurve of the undisturbed lacustrine soft clay is greater than that of the remolded soil,and theλ-γcurve of the undisturbed soil is always smaller than the remodeled soil.When the dynamic shear strain is large,the dynamic shear modulus G of the undisturbed soil drops sharply and approaches the remolded soil.The relative difference of the G_(max),the different of G/G_(max)-γandλ-γfitting curve between the undisturbed and the remolded soil decreases with the increase of the consolidation confining pressure.By comparing with the research results of other scholars,it was found that sedimentary environment was not the determining factor of soil dynamic characteristics.The dynamic characteristics of soft clay in the same sedimentary environment but different regions would also be different.Through quantitative analysis of the microstructure parameters,it is found that with the increase of consolidation confining pressure,the average area and the average maximum diameter of the undisturbed soil particles and pores are decreased,but the difference is not obvious in the remolded soil,and the relative difference of the microstructure parameters is positively correlated with the relative di

关 键 词：湖泊相软黏土 原状土 重塑土 动剪切模量 阻尼比 微观结构参数 

分 类 号：TU4[建筑科学—土工工程]